FouriScale: A Frequency Perspective on Training-Free High-Resolution Image Synthesis

     

Linjiang Huang^1,2*, Rongyao Fang^1,*, Aiping Zhang³, Guanglu Song⁴, Si Liu⁵, Yu Liu⁴, Hongsheng Li^{1,2 ✉️}

¹CUHK-SenseTime Joint Laboratory, The Chinese University of Hong Kong
²Centre for Perceptual and Interactive Intelligence
³Sun Yat-Sen University, ⁴Sensetime Research, ⁵Beihang University
* Equal contribution, ✉️Corresponding author

🔥🔥🔥 We have released the code, cheers!

⭐ If FouriScale is helpful for you, please help star this repo. Thanks! 🤗

📖 Table Of Contents

• Update
• TODO
• Abstract
• Visual Results
• Setup
• Inference

🆕 Update

• 2024.03.25: The code is released 🔥
• 2024.03.20: 🎉 FouriScale has been selected as 🤗 Hugging Face Daily Papers 🔥
• 2024.03.19: This repo is released 🔥

⌛ TODO

• Release Code 💻
• Update links to project page 🔗
• Provide Hugging Face demo 📺

🎆 Abstract

In this study, we delve into the generation of high-resolution images from pre-trained diffusion models, addressing persistent challenges, such as repetitive patterns and structural distortions, that emerge when models are applied beyond their trained resolutions. To address this issue, we introduce an innovative, training-free approach FouriScale from the perspective of frequency domain analysis. We replace the original convolutional layers in pre-trained diffusion models by incorporating a dilation technique along with a low-pass operation, intending to achieve structural consistency and scale consistency across resolutions, respectively. Further enhanced by a padding-then-crop strategy, our method can flexibly handle text-to-image generation of various aspect ratios. By using the FouriScale as guidance, our method successfully balances the structural integrity and fidelity of generated images, achieving an astonishing capacity of arbitrary-size, high-resolution, and high-quality generation. With its simplicity and compatibility, our method can provide valuable insights for future explorations into the synthesis of ultra-high-resolution images.

👀 Visual Results

Visual comparisons

⭐ Visual comparisons between ① ours, ② ScaleCrafter and ③ Attn-Entro, under settings of 4× (default height×2, default width×2), 8× (default height×2, default width×4), and 16× (default height×4, default width×4), employing three distinct pre-trained diffusion models: SD 1.5, SD 2.1, and SDXL 1.0.

Visual results with LoRAs

⭐ Visualization of the high-resolution images generated by SD 2.1 integrated with customized LoRAs (images in red rectangle) and images generated by a personalized diffusion model, AnimeArtXL.

Visual results with more resolutions

⚙️ Setup

conda create -n fouriscale python=3.8
conda activate fouriscale
pip install -r requirements.txt

⭐ We highly recommend following the provided environmental requirements, especially regarding diffusers, as there are significant modifications between versions.

💫 Inference

Text-to-image higher-resolution generation with diffusers script

stable-diffusion xl v1.0 base

# 2048x2048 (4x) generation
accelerate launch --num_processes 1 \
text2image_xl.py \
  --pretrained_model_name_or_path stabilityai/stable-diffusion-xl-base-1.0 \
  --validation_prompt 'Polenta Fritters with Asparagus & Eggs' \
  --seed 23 \
  --config ./configs/sdxl_2048x2048.yaml \
  --logging_dir ${your-logging-dir}

To generate in other resolutions, change the value of the parameter --config to:

• 2048x2048: ./configs/sdxl_2048x2048.yaml
• 2560x2560: ./configs/sdxl_2560x2560.yaml
• 4096x2048: ./configs/sdxl_4096x2048.yaml
• 4096x4096: ./configs/sdxl_4096x4096.yaml

Generated images will be saved to the directory set by ${your-logging-dir}. You can use your customized prompts by setting --validation_prompt to a prompt string or a path to your custom .txt file. Make sure different prompts are in different lines if you are using a .txt prompt file.

--pretrained_model_name_or_path specifies the pretrained model to be used. You can provide a huggingface repo name (it will download the model from huggingface first), or a local directory where you save the model checkpoint.

You can create your custom generation resolution setting by creating a .yaml configuration file and specifying the layer to use our method. Please see ./assets/layer_settings/sdxl.txt as an example.

If the stable-diffusion xl model generate a blurred image with your customized prompt, please try --amp_guidance for a stronger guidance.

stable-diffusion v1.5 and stable-diffusion v2.1

# sd v1.5 1024x1024 (4x) generation
accelerate launch --num_processes 1 \
text2image.py \
--pretrained_model_name_or_path runwayml/stable-diffusion-v1-5 \
--validation_prompt "Polenta Fritters with Asparagus & Eggs" \
--seed 23 \
--config ./configs/sd1.5_1024x1024.yaml \
--logging_dir ${your-logging-dir}

# sd v2.1 1024x1024 (4x) generation
accelerate launch --num_processes 1 \
text2image.py \
--pretrained_model_name_or_path stabilityai/stable-diffusion-2-1-base \
--validation_prompt "Polenta Fritters with Asparagus & Eggs" \
--seed 23 \
--config ./configs/sd2.1_1024x1024.yaml \
--logging_dir ${your-logging-dir}

To generate in other resolutions please use the following config files:

• 1024x1024: ./configs/sd1.5_1024x1024.yaml ./configs/sd2.1_1024x1024.yaml
• 1280x1280: ./configs/sd1.5_1280x1280.yaml ./configs/sd2.1_1280x1280.yaml
• 2048x1024: ./configs/sd1.5_2048x1024.yaml ./configs/sd2.1_2048x1024.yaml
• 2048x2048: ./configs/sd1.5_2048x2048.yaml ./configs/sd2.1_2048x2048.yaml

Please see the instructions above to use your customized text prompt.

😃 Citation

Please cite us if our work is useful for your research.

@article{2024fouriscale,
  author    = {Linjiang Huang, Rongyao Fang, Aiping Zhang, Guanglu Song, Si Liu, Yu Liu, Hongsheng Li},
  title     = {FouriScale: A Frequency Perspective on Training-Free High-Resolution Image Synthesis},
  journal   = {arxiv},
  year      = {2024},
}

📓 License

This project is released under the Apache 2.0 license.

💡 Acknowledgement

We appreciate ScaleCrafter for their awesome work and open-source code.

✉️ Contact

If you have any questions, please feel free to contact ljhuang524@gmail.com.